OPTICAL-PHONON BEHAVIOR IN ZN1-XMNXSE - ZINCBLENDE AND WURTZITE STRUCTURES

Optical phonons of mixed-crystal Zn1-xMnxSe in both zinc-blende and wurtzite structures are investigated by Raman scattering. A calculation of the compositional dependence of the optical-phonon frequency in Zn1-xMnxSe is performed using a modified random-element isodisplacement model with some detailed consideration. It confirms that Zn1-xMnxSe shows an intermediate-mode behavior. The constant THETA which describes the effect of variation of the lattice parameter on the force constants should be different for individual mixed crystals. The phonon-mode splitting in wurtzite-structure Zn1-xMnxSe is mainly attributed to the directional dependence of the force constants.